1. Field of The Invention
The present invention relates to a method of detecting a longitudinal direction of an inspection object such as an electronic component and identifying a configuration of the same.
2. Description of The Prior Art
A mounting apparatus installs electronic components on a substrate, on the upper surface of which a printed circuit pattern is formed. A suction nozzle holds an electronic component. At an observation position, a camera measures or detects an absorption point of the suction nozzle to the electronic component, a direction of the electronic component, an absorption angle on a horizontal plane etc. An adjustment is carried out on the basis of these measured or detected data to correct a shift distance (shift stroke) of the suction nozzle and a rotational angle of the suction nozzle about its rotational axis. Thereafter, the electronic component is conveyed to and installed on a predetermined position of the substrate. This installation operation cannot be accomplished without detecting a longitudinal direction of the electronic component.
A conventional method of detecting a longitudinal direction of an electronic component was carried out by chiefly detecting each corner of the electronic component. By knowing all of corners, the longitudinal direction of the electronic component can be identified. The suction nozzle, however, tended to cause an error in such a conventional detection method. Because, the absorption point of the suction nozzle is not stable on the electronic component. It may offset widely toward a corner of the electronic component. The camera, observing these suction nozzle and electronic component, will produce an image of the electronic component superposed by an image of the suction nozzle at the corner thereof. In such a case, the detecting operation will fail to detect this superposed corner, resulting in an unaccomplished detection of the longitudinal direction of the electronic component.
Furthermore, if a rectangular electronic component has a plurality of leads laterally extending from both sides of the rectangular electronic component as shown in FIG. 7B, edges of these leads will cause confusion in the detection of the longitudinal direction because more than 4 edges will be detected by the camera. This will make it difficult to identify 4 corners of the rectangular electronic component. It is difficult to judge whether each edge belongs to the electronic component or to the lead.